Non-foaming detergents



United States Patent 2,751,358 NON-FOAMING DETERGENTS Maximilian Caviiit, The Hague, Netherlands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application November 14, 1950,

Serial No. 195,709

Claims priority, application Great Britain November 28, 1949 3 Claims. (Cl. 252-153) This invention relates to non-foaming detergent compositions and to the suppression of foam in aqueous solutions of detergents, emulsifying agents and the like. It deals particularly with an effective foam-suppressing composition which is especially useful with surface-active agents. a

The production of foam is particularly undesirable in many industries utilizing aqueous solutions of surfaceactive compounds such as the numerous synthetic wetting, detergent and emulsifying agents presently available. Solutions of such sourface-active agents are extensively used, for example, in the textile industry for scouring the raw material and in dyeing and other treating liquors, in leather manufacture, in laundries and in dish and bottle washing machines, and since it is usually necessary to either move the goods through the liquors or to circulate the liquors by stirring or other means, an excessive and undesirable amount of foam frequently results.

The present invention provides a method of reducing or inhibiting the formation of foam in aqueous systems and anti-foaming compositions which may be utilized for this purpose. It has as an important object the suppression of foaming of alkyl sulfate salt and alkyl aryl sulfonate detergents. Other objects and advantages of the invention will be apparent from the followingdescription.

The invention is based upon the unexpected discovery that compositions containing in combination two essential components, namely, certain high molecular Weight polyamides and a substantially water-immiscible organic liquid, possess powerful anti-foaming properties which may be most effectively utilized to reduce or inhibit foaming in a very wide diversity of aqueous systems. This :discovery is all the more surprising in that attempts to 'use these high molecular weight polyamides without the aforesaid water-immiscible organic liquids reveal that apart from one or two veryspecific applications they are substantially ineffective in preventing foaming of the same diversity of aqueous systems, and, in particular, are quite. ineffective in suppressing the foaming of detergent solutions containing sufiicient detergent for eifective wash-* ing, i. e. about 0.1% or more of detergent.

According to the present invention, therefore, an antifoaming composition comprises a fine suspension in a substantially water-immiscible organic liquid of one or more organic compounds containing in the molecule at least two groups of the general formula RCONR1- wherein R represents an aliphatic or cycloaliphatic radical containing at least carbon atoms and-R1 represents a hydrogen atom or an organic radical, said groups being either joined directly together or joined by means -of a polyvalent organic radical.

This polyvalent organic radi- .7

cal may be an aliphatic, cycloaliphatic oraromatic radical.

The polyamides used in preparing .the antifoaming compositions of the invention may, *ifdesired, contain'substituent groups as, for ex vantageous. ample," amino, hydroxy], ester and ether groups. The preferred compounds are the 2,751,358 Patented June 19, 1956 2 diacyl or polyacyl derivatives of the polyalkylene polyamines in which the acyl radicals are derived from carboxylic acids having at least 11 carbon atoms per'molecule, for example, from the higher fatty acids such as lauric, palmitic, oleic and stearic acids, hydroxy acids such as ricinoleic acid, or from naphthenic acids such as are obtained as by-products from the refining of petroleum. Suitable polyamines from which effective diacyl or polyacyl derivatives can be prepared include ethylene diamine, diethylene triamine, triethylene tetramine, hexamethylene diamine, decamethylene diamine, hydroxyethyl ethylene diamine and 1:3-diamino-2-propanol. Examples of amides which have been found to be advantageous are N,N-distearyl ethylene-diamide, N,N'-dioleyl hexamethylene diamide, N,N-dilauryl decamethylene diamide, N,N'-dinaphthenyl ethylene diamide, tristearyl diethylene triamide, the palmityl ester of N,N'-diplamityl- N'-beta-hydroxyethyl ethylene diamide and the lauryl ester of 1:3-di(laurylamido)-2-propanol.

The organic liquids which are used in preparing the antifoaming compositions of the invention are substantially water-immiscible and preferably have a solubility in water of not more than about 03%. Preferably they are also substantially non-volatile at the temperature at which the compositions are to be used and are non-solvents or relatively poor solvents for the polyamides at such temperatures. Furthermore, the liquid employed should not react with the polyamide or the constituents of the liquid which is to be treated with the anti-foaming composition. Petroleum hydrocarbon distillates boiling above about C., such as white spirit, kerosene and light lubricating oils such as spindle oil, are the preferred liquids. More viscous oils such as heavy lubricating oils and fuel oils may also be used but are generally less suitable. Other organic liquids which can be used are the higher alcohols, preferably of six or more carbon atoms per. molecule, particularly those with branched carbon chains or with the hydroxyl group occupying a non-terminal position of the carbon chain, such as secondary hexyl and heptyl alcohols and the like, the ketones correspondingv to such alcohols such, for example, as diisobutyl ketone, etc., and the higher esters as the secondary amyl acetates and higher homologues, and halogenated, especially chlorinated, hydrocarbons which fulfill the above conditions. In some instances, these organic liquids may also possess antifoaming properties to a greater or lesser degree as," for example, the higher alcohols and esters. The hydrocarbon liquids which are preferred in the compositions of the invention themselves show some antifoaming properties. These antifoaming properties are, however, relatively weak and in practice it is found that when using such hydrocarbons by themselves as antifoaming agents the foam is readily reformed when the aqueous liquid is again agitated. The antifoaming. compositions of the invention may be prepared by any conventional technique. A convenient method is to heat the polyamides in the organic liquid to a temperature at which solution takes place and then to cool the solution rapidly with vigorous stirring or shaking whereupon the polyamide separates as a dispersion of fine particles. Alternatively, the solidpolyamide may be ground with the liquid to the required degree of fineness in any suitable type of mill or other disintegrator.

The relative proportions of polyamide and waterimmiscible organic liquid used in preparing the compositions of the invention may vary within very Wide limits. Since it is usually desired to control the amount of com- 'position added to any given foaming system, a composition which is readily pourable will, in generally be ad- The proportions chosen in any given case will be influenced in some degree by the nature of the foaming system to be treated. As a rule about 0.05% to about 10% by weight by polyamide based upon the weight Equally good results are obtained when using N,N- of water-immiscible liquid used is satisfactory. dilauryl ethylene diamide or NAT-distearyl hexamethyl- The powerful antifoaming properties of the composiene diamide instead of N,N-distearyl ethylene diamide tions of the invention may be demonstrated by adding under the above conditions. a few drops of a finely divided suspension of N,N'- 5 The detergent Teepol referred to above and throughdistearyl ethylene diamide in white spirit to a foaming out the specification is a mixture of sodium salts of secdilute aqueous solution of a mixture of sodium salts of ondary alkyl sulfates wherein the alkyl groups contain the higher secondary alkyl sulfuric esters, such as are from to 18 carbon atoms produced by neutralizing marketed under the registered trademark Teepol, when sulfation products of a Cio-Cis alkene cracking fraction. there is an immediate and total collapse of the foam. 10 The antifoaming properties of the compositions of the Attempts to reform the foam by shaking the liquid are invention equally effective in neutral, alkaline or acid ineffective, complete inhibition of foaming being achieved media. This can be seen from Table II which gives the with no detrimental effect on the wetting or detergent results of tests on the antifoaming properties of a suspower of the solution or on its content of active material. pension of N,N-distearyl ethylene diamide in odorless Similar results are obtained using a dispersion of N,N'- kerosene on neutral, acid and alkaline solutions of distearyl hexamethylene diamide in White spirit. Te'epol carried out as described above, the temperature The antifoaming properties of the composition of the being maintained at 70 C. throughout the tests.

Table II.-Foaming trials with N,N-distearyl ethylene diamide (DSED)-kerosene suspensions in aqueous Teepol solutions at 70 C.

Foam Vol0ume (m1.) of Detergent Solution Weight of Concenffra- 3% wtJvol. Teepol tion m 100 ml the kerosene Neutral +20% wt./vol. +20% wt./vol. detergellt suspension NaOH H2504 solution $2 F0 F10 0 Fro Fa Fro Nil Nil 182 45 153 33 182 22 2. 6 Nil Nil Nil Nil Nil Nil 0.001 g 0.5 Nil Nil Nil Nil Nil Nil 0. 25 Nil Nil Nil Nil Nil Nil invention are quantitatively demonstrated in Table I in The amount of the dispersed polyamide necessary to which are given the results of foaming tests carried out achieve adequate protection against foaming varies with at room temperatures (15 C.) with undiluted Teepol the particular conditions of the system to be treated and solutions and diluted aqueous solutions containing 1 the particular polyamide employed. Thus, the temperaper cent, 0.1 per cent and 0.01 per cent by weight of ture' of the system to be treated has a substantial effect Teepol and varying amounts of a suspension of N,N- do on the concentration of the polyamide required. With distearyl ethylene diamide in white spirit containing 0.6 g. increasing temperature, foam becomes increasingly unof diamide per liter of suspension. For comparison, the stable and therefore correspondingly smaller amounts of results of identical trials made with equivalent amounts antifoaming composition will be required to inhibit foam of white spirit alone are given in brackets. It can readily formation in aqeous liquids as the temperature is raised. be seen that addition of as little as one part per million For example, foaming is completely suppressed in a 0.1 of the diamide in the form of a suspension in white spirit per cent Teepol solution with 2 p. p. m. of diamide at produces a striking decrease in the amount of foam. 80 C., while at 15 C. about p. p. m. are desirable In these tests, the calculated amount of antifoaming for this purpose. In general amounts within the range compositions was introduced into a 250 ml. graduated of from 1 to 500 parts of polyamide per million parts stoppered measuring cylinder, made up to ml. with 50 of aqueous detergent solution are added as a suspension Teepol solution and the cylinder inverted 25 times. containing 0.05% to 10% of the polyamide in an organic The volume of liquor and of liquor plus foam were read liquid boiling above C. and having a solubility in separately 30 seconds after inversion and again after water of not more than about3%. standing for 10 minutes. The results are expressed as The foam inhibiting compositions of the invention are the volume of foam (obtained by difference) 30 seconds 55 advantageously prepared in the form of suspensions of (F and 10 minutes (Fm) after the inversion operation. fine particles of polyamides in water-immiscible organic Table I.-F0aming trials with N,N-distearyl ethylene diamide (DSED)-white spirit suspension in aqueous Teepol solutions at 15 C.

FOAM VOLUMES (mL) p. p. m. DSED added 0 1 2 a 10 20 so 200 Strength of "Teepol" Solution: Undiluted Teepol"- 220 35(220) 35 (220) 23(180) 8(220) 10(220) 1 0 7(90) 7(60) 0(40) 0(90) 0(60) 7 0 220 (210) 45090) 12080) 10070) 10(180) 2(60) 0(55) 0(40) 0(30) 0(50) 130 24030) 8020) 10(110) 0(40) 120 sure) 1(90) 0(60) 0(23) 1 Using 6 g/l. DSED in white spirit. All other results using0.6 g/l. DSED in white spirit.

liquids, stabilized in the form of emulsions. Thereby, compositions are made available in which there is substantially no tendency for the polyamide particles to separate out on standing. These emulsions may be produced with the aid of any of the usual emulsifying agents of the anionic, cationic or non-ionic types as, for example, the alkali metal salts of higher alkyl sulfuric acid esters and alkyl aryl sulfonic acids, metal salts of higher fatty acid, quaternary ammonium salts containing a long chain alkyl group attached to the nitrogen atom and condensation products of alkyl phenols with ethylene oxide. The emulsions are preferably of the water-in-oil type containing about toabout 60% of water. Since the abovespecified polyamides themselves promote the formation of emulsions of the water-in-oil type, it is necessary to incorporate onlya relatively small proportion, for example, about 0.05% to about 5%, of any further emulsifier used. Teepol, for instance, is very suitable as an emulsifier for preparing such a water-in-oil type emulsion as is described in the following example where the weightvolume relationship is that of the kilogram to the liter.

A solution of N,N-distearyl ethylene diamide, prepared by dissolving 1 part by weight of the amide in 40 parts by volume of odorless kerosene at 110 C., was cooled to 70 C. and a solution of 40 parts by volume of water containing 0.6 part by volume of Teepol also at 70 C. was gradually added with stirring. The coarse suspension obtained was cooled to room temperature and passed through a colloid mill when a stable, creamy-white emulsion was obtained. A small amount of creaming, which occurred when the emulsion was allowed to stand for several days, was readily dispersed again by shaking. This slight creaming elfect may, if desired, be reduced or eliminated by incorporating a small quantity of an additional water-in-oil emulsifier. For example, quantities of about 0.1 up to 1.6 per cent by weight, based on the total composition, of magnesium stearate have been found very effective for this purpose, quantities of from 0.5 to 0.9 per cent by weight usually being suflicient. A small quantity of pine oil or other perfume may be added to impart a pleasant odor to the composition.

A sample of the emulsion prepared above to which a small quantity of pine oil had been added as a deodorant was tested in a mechanical dish washing machine of approximately 22 gallons capacity filled with a washing liquor containing 0.57 per cent by weight of Teepol at 90 C. There was almost complete inhibition of foaming during the whole period the machine was in operation minutes) when 100 ml. of the above emulsion was added to the washing liquor. The cleansing properties of the Washing liquor were unaffected by the addition of the above emulsion and no residual odor was left on the dishes.

Completely satisfactory results are also obtained with a similar washing liquor containing Teepol and the above distearyl ethylene diamide emulsion when used in mechanical washing machines of the jet pressure type as used in dairies.

The antifoaming compositions of this invention may be added either to the aqueous systems in which foaming is to be prevented or to any liquid ingredients which are to be used in the making of such aqueous systems. Thus, in using the antifoaming compositions to prevent the foaming of aqueous washing liquors, the composition may be added to the washing liquor during use, or to the solutions of surface-active material used in making the washing liquor or even to the water before the surface-active ma terial is added thereto.

Particularly advantageous are the antifoaming compositions of the invention incorporated in concentrated solutions of surface-active agents or detergents to produce nonfoaming compositions which, when diluted with water to a suitable concentration for use, maintain their non-foaming characteristics under normal conditions of use or under condition-s of use for which the compositions are particularly intended. For example, addition of 1.5 parts by described in United States volume of a suspension containing 60 grams per liter of N,N'-distearyl ethylene diamide in white spirit to 60 parts by volume of neat Teepol gave a non-foaming liquid which did not foam when diluted to an aqueous solution containing 1 per cent by weight of Teepol. In general, compositions containing about 0.5 to about 10 parts by volume of asuspension of a polyamide in a water-immiscible liquid of the type previously described containing about 10 to grams of the polyamide per liter are used per 100 parts by volume of detergent solution containing from about 10% to 60% by weight of detergent.

The production of such non-foaming concentrates is of particular'value for horticultural and agricultural spray compositions in the preparation of which Spreaders are incorporated to facilitate wetting of the trees and plants by the spray. These spreaders are compositions containing high concentrations of wetting agents, for example, Teepol, and the excessive foaming which occurs on mixing may prove a considerable drawback. Such foaming can, however, be efiiciently suppressed by incorporating the requisite proportion of the antifoaming suspensions 0r emulsions of this invention in the spreader prior to use.

While the invention has been particularly described with reference to antifoaming compositions comprising dispersions of N,N'-diacyl alkylene diamides in white spirit or kerosene, and to the defoaming of aqueous solutions of Teepol by means of these compositions, this is by way of illustration only and in no way limits the scope of the invention. The compositions of the invention are equally effective in reducing or inhibiting foam in aqueous liquids containing other surface-active agents of the anionic, cationic or non-ionic type. Examples of surface-active agents with which the antifoaming compositions are effective are, for instance, the sulfonate detergents which include the water-soluble salts of organic sulfonic acids and sulfate esters having an alkyl group of 8 to 20 carbon atom-s such, for instance, as the alkali metal salts of the monosulfonates of the alkylated aromatic hydrocarbons of the benzene series having an alkyl group of 10 to 18, preferably 12 to 16, carbon atoms. Alkyl benzene or toluene sulfonates, such as are described in United States Patents 2,467,130-32 and 2,477,283, are typical of such sulfonate salts. The keryl benzene and toluene sulfonates Patent 2,340,654 are other examples of detergents which can advantageously be improved by use with the composition-s of the invention. Alkyl sulfonic acid salts, such as are described in United States Patents 2,187,338 and 2,276,090, for example, are another sub-group of detergents which can be made effectively non-foaming by use of the new compositions. In addition to the secondary alkyl sulfate salts of 8 to 20 carbon atoms already described which are produced from olefins, preferably cracked wax olefins, those obtained from alcohols, as shown in United States Patents 1,968,794 and 2,047,612, for example, can be similarly used. Quaternary ammonium salts and non-ionic detergents, such as are obtained by condensing alkyl phenols with ethylene oxide, and the like are further examples of surface-active agents with which the new compositions can be used. These antifoaming compositions are also effective in aqueous compositions containing naturally occurring foaming agents as, for example, in glue, casein, hydrolyzed proteins, paper pulp and yeast manufacture, and in various chemical processes such as the neutralization of sulfuric acid sludge from petroleum refining processes with chalk or the like.

Instead of the diacyl alkylene diamides which have been given as examples, one can use other polyamides such, for instance, as N,N'-dilauryl meta-phenylene diamine, N,N-distearyl hydrazine, N,N'-dioleyl piperazine, and the like. The polyamides need not be symmetrical but can be compounds such, for example, as lauryl stearyl ethylene diamide, etc. Mixtures of two or more polyamides of carboxylic acids having 10 or more, preferably 10 to 18, carbon atoms in the acyl radicals, such as are obtained by reacting mixtures ofcarboxylic acids, for example, the mixed acids of natural oils or fats such as coconut oil, soyabean oil, fish oil and like acids, with one or more polyamines, can be used in place of the individual chemical compounds described. While all these polyamides are not exact equivalents and some are more eflicient than others, suspensions of any of them in a substantially water-immiscible organic liquid in accordance with the invention have been found to be effective foam inhibitors when used in the proper amount.

The compositions of the invention may also be used to prevent foaming in systems in which water does not form the major constituent. Thus, fuel oils containing more than about 1 per cent of water foam excessively when heated. Similar foaming is encountered in gas works where aqueous tar oil emulsions are broken by heating. Further, lubricating oils tend to become contaminated with small quantities of water during use, and under certain conditions as, for example, the presence of detergent salts in the oil, a troublesome amount of foam may occur which can result in lubricating failures and excessive wear, and even seizure of the lubricated parts. Foaming in such systems is effectively prevented by incorporating a small proportion of a dispersion or emulsion of the invention. For these purposes, it may be preferable to utilize as the water-immiscible liquid a hydrocarbon oil comparable in viscosity and/ or boiling range with the oil to be treated.

It will thus be seen that the invention is capable of wide variation not only in regard to the polyamides which can be used and the water-immiscible liquids in which they can be suspended, but also in regard to the detergent and other systems in which they are eifective foam inhibitors. Still other variations can be made in the invention which is therefore not limited to the examples given by way of illustration nor by any theory proposed in explanation of the improved results which are obtained.

I claim as my invention:

1. A detergent composition comprising an aqueous solution of a mixture of sodium salts of secondary alkyl sulfates wherein the alkyl groups contain from 10 to 18 carbon atoms produced by neutralizing sulfation products of a ClO-C18 alkene fraction together with a suspension in a substantially water-immiscible liquid hydrocarbon boiling above C. of a N,N-diacyl polymethylene diamide wherein the acyl groups are aryl groups of higher fatty acids having from 12 to 18 carbon atoms and the polymethylene group contains from 2 to 6 carbon atoms, said suspension containing about 0.05 to about 10% by weight of said diamide based on the weight of said liquid hydrocarbon and said polyamide being present in an amount of 1 to 500 p. p. m. of said aqueous solution.

2. A detergent composition as in claim 1 wherein the polyamide is N,N'-distearyl ethylene diamide.

3. A detergent composition as in claim 1 wherein the liquid hydrocarbon is a petroleum distillate having a viscosity not great than that of spindle oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,833,772 Bradshaw Nov. 24, 1931 2,347,178 Fritz et a1. Apr. 25, 1944 2,416,503 Trautman et al. Feb. 25, 1947 2,423,214 Wells July 1, 1947 2,469,493 Barker May 10, 1949 2,534,441 Gunderson Dec. 19, 1950 2,588,345 Bird et a1. Mar. 11, 1952 FOREIGN PATENTS 568,510 Great Britain Apr. 9, 1945 OTHER REFERENCES I. I. E. C., vol. 40, No. 8 (August 1948), pages 1363-1370. 

1. A DETERGENT COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF A MIXTURE OF SODIUM SALTS OF SECONDARY ALKYL SULFATES WHEREIN THE ALKYL GROUPS CONTAIN FROM 10 TO 18 CARBON ATOMS PRODUCED BY NEUTRALIZING SULFATION PRODUCTS OF A C10-C18 ALKENE FRACTION TOGETHER WITH A SUSPENSION IN A SUBSTANTIALLY WATER-IMMISCIBLE LIQUID HYDROCARBON BOILING ABOVE 100* C. OF A N,N''-DIACYL POLYMETHYLENE DIAMIDE WHEREIN THE ACYL GROUPS ARE ARYL GROUPS OF HIGHER FATTY ACIDS HAVING FROM 12 TO 18 CARBON ATOMS AND THE POLYMETHYLENE GROUP CONTAINS FROM 2 TO 6 CARBON ATOMS, SAID SUSPENSION CONTAINING ABOUT 0.05 TO ABOUT 10% BY WEIGHT OF SAID DIAMIDE BASED ON THE WEIGHT OF SAID LIQUID HYDROCARBON AND SAID POLYAMIDE BEING PRESENT IN AN AMOUNT OF 1 TO 500 P.P.M. OF SAID AQUEOUS SOLUTION. 